EXPLANATION OF PLATE V. 



Fig. 1. — Lateral view of a dissected female Hilsa to show the infected 

 mesentery and liver, and the other viscera. The heart and 

 ovary of the left side are removed. 



2. — A cyst of Ilisha 'parthenogenetica n. g., n. sp. 



3. — An adult individual of I. parthenogenetica dissected out of the 

 cyst. 



4. — Surface view of the rostellum and the four suckers on the 

 anterior extremity of an individual of /. parthenogenetica. 



5. — Parthenogenetic eggs of /. parthenogenetica. 



6. — Morula stages in the development of the parthenogenetic 

 eggs of /. parthenogenetica. 



7. — Anterior extremity of an adult individual of I. partheno- 

 genetica with a young one escaping out of it. 



8. — A young individual of I. parthenogenetica lying free in the 

 mesentery of Hilsa, before the formation of the cyst. 



Reference Lettering. 



E., Eggs. E{i)., Morula stage in the development of eggs. E.t., Excretory tube. 

 Int., Intestine. L-, Liver. L{i), Part of the liver infected with cysts of 1. 2^a>'fheno- 

 genetica. La., Larva escaping out of the mother individual. M., Mesentery infected 

 with /. parthenogenetica. Ov., Ovary. B.C., Pigment corpuscles, i?., Rostellum. 

 S., Sucker. 



